The present invention is directed to cooling assemblies and other apparatus used for removing heat from electronic devices. More particularly, the present invention is directed to an apparatus for cooling an electronic module through the utilization of a thermal spreader. Even more particularly, this invention is directed to a thermal spreading plate having a thermal interface on only a portion of a main surface thereof. The thermal interface is positioned to align to an area of higher heat flux on a surface of the heat generating element to be cooled.
As is well known, as the circuit density of electronic chip devices increases, there is a correspondingly increasing demand for the removal of heat generated by these devices. The increased heat demand arises both because the circuit devices are packed more closely together and because the circuits themselves are operated at increasingly higher clock frequencies. Nonetheless, it is also known that runaway thermal conditions and excessive heat generated by chips is a leading cause for failure of chip devices. Furthermore, it is anticipated that the demand for heat removal from these devices will increase indefinitely. Accordingly, it is seen that there is a large and significant need to provide useful cooling mechanisms for electronic circuit devices.
Complementary metal oxide semiconductor (CMOS) processing has progressed to the point where multiple logic units (such as processors) and their associated control and support circuits (e.g., memory) are being placed on a single integrated circuit chip. From a thermal viewpoint, this results in a chip with a highly non-uniform heat flux distribution. A relatively high heat flux is generated in the processor core region(s) and a relatively low heat flux is produced by the control/support regions. In fact, the core region heat flux can be as much as fifteen times greater than that of the other regions. Thermal paste conduction cooling schemes are not well suited to handle such disparate fluxes. They result in an equally disparate circuit temperature distribution, and more importantly, a much higher absolute junction temperature within the high heat flux regions.
To summarize the present invention, therefore, provided herein in one aspect is a thermal dissipation assembly for facilitating cooling of an electronic device, such as an electronic module. The thermal dissipation assembly includes a thermal spreader which has a surface that is configured to thermally couple to a surface of a heat generating component of the electronic device. The heat generating component has a non-uniform thermal distribution across the surface thereof between at least one first region of the surface and at least one second region of, the surface. The at least one first region has a higher heat flux than the at least one second region. The thermal dissipation assembly further includes a thermal interface coupled to the surface of the thermal spreader for facilitating heat transfer between the heat generating component and the thermal spreader when the thermal spreader is disposed with the thermal interface in contact with the surface of the heat generating component, wherein the thermal interface covers only a portion of the surfaces of the thermal spreader and the heat generating component. In one embodiment, the thermal interface is configured to align to at least a portion of each first region of the surface of the heat generating component having the higher heat flux.
In another aspect, an electronic device is provided having an integrated circuit chip with a non-uniform thermal distribution across a surface thereof between at least one first region of the surface and at least one second region of the surface. The at least one first region has a higher heat flux than the at least one second region. The electronic device further includes a thermal dissipation assembly comprising a thermal spreader and a thermal interface. The thermal spreader has a surface thermally coupled to the surface of the integrated circuit chip, with the thermal interface disposed between the surfaces of the thermal spreader and integrated circuit chip to thermally connect the spreader and the chip. The thermal interface is designed to cover only a portion of the surface of the integrated circuit chip to selectively control thermal coupling between the integrated circuit chip and the thermal spreader.
In a further aspect, a thermal dissipation method is provided for an electronic device having a heat generating component. The method includes: providing a thermal spreader having a surface which is to thermally couple to a surface of the heat generating component, wherein the heat generating component has a non-uniform thermal distribution across its surface between at least one first region of the surface and at least one second region of the surface, and wherein the at least one first region has higher heat flux than the at least one second region; and providing a thermal interface for the surface of the thermal spreader for facilitating heat transfer between the heat generating component and the thermal spreader when the thermal spreader is disposed with the thermal interface in contact with the surface of the heat generating component, wherein the thermal interface covers only a portion of the surface of the thermal spreader to selectively thermally couple the thermal spreader to the surface of the heat generating component.
To restate, provided herein is a thermal spreader and interface assembly useful in cooling a heat generating component such an integrated circuit chip. The thermal interface resides on only a portion of the surface of the thermal spreader designed to couple to a surface of the heat generating component. When in use, heat dissipation is facilitated in those regions where the thermal interface physically connects the surfaces of the thermal spreader and the heat generating component, while an air gap limits direct thermal transfer in the remaining portions of the surfaces of the thermal spreader and heat generating component. By selectively placing the thermal interface, enhanced cooling performance can be obtained by allowing handling of high heat flux zones on a component, such as an integrated circuit chip, while still cooling the entire component to acceptable temperatures thereby establishing a more uniform temperature distribution on the component. This advantageously facilitates integrated circuit design and operation.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered part of the claimed invention.